摘要
基于光和物质相互作用的密度矩阵方程理论,研究了双光场作用下里德伯原子的瞬态吸收特性。当耦合场较弱时,探测吸收随时间增加到最大值后,再单调递减至零;随着耦合场拉比频率的增加,探测吸收的最大值增大;当拉比频率增加到一定程度时,吸收峰值逐渐减小,吸收随时间延长出现振荡。当耦合场拉比频率取值合适时,出现明显的负吸收现象。通过分析粒子数布居及相干项随时间的演变可知,耦合、探测场共同作用引起的相干项导致了负吸收现象的出现。
The transient absorption properties of Rydberg atoms driven by two pulsed laser fields are investigated herein on the basis of the theory of density matrix equation,which describes the interaction of photon and material.It is found that owing to the weak coupling field,the probe absorption first increases to the maximum value and then decreases monotonically to zero with time.The maximum value of the probe absorption increases with an increase in Rabi frequency until the largest value is obtained.Then,it decreases gradually and the absorption with time presents the character of oscillation at the same time.When the coupling field’s Rabi frequency is appropriate,the phenomenon of negative absorption occurs.The analysis of the evolution of population and the coherent term with time reveals that the coherent term caused by the influence of the coupling and probe field results in a negative absorption.
作者
张贵银
赵轩
李松涛
郑海明
Zhang Guiyin;Zhao Xuan;Li Songtao;Zheng Haiming(School of Mathematics and Physics,North China Electric Power University,Baoding 071003,Hebei,China;Department of Mechanical Engineering,North China Electric Power University,Baoding 071003,Hebei,China)
出处
《激光与光电子学进展》
CSCD
北大核心
2022年第11期151-156,共6页
Laser & Optoelectronics Progress
基金
国家自然科学基金(11174078)
河北省自然科学基金(A2019502044)。
关键词
原子与分子物理学
非线性光学
密度矩阵方程
里德伯原子
负吸收
atomic and molecular physics
nonlinear optics
density matrix equation
Rydberg atom
negative absorption
